Database / ValKey Interview questions
Explain the lifecycle of a command from a Valkey client to execution and response?
A client encodes its request using the RESP protocol and sends it over a TCP connection; an I/O thread (or the main thread, in older configurations) reads the bytes off the socket and parses them into a command.
flowchart TD
A[Client sends RESP command] --> B[I/O Thread: read + parse]
B --> C[Main Thread: dispatch to command table]
C --> D[Execute against in-memory keyspace]
D --> E[Propagate to AOF buffer]
D --> F[Propagate to replication backlog]
D --> G[Encode RESP reply]
G --> H[I/O Thread: write reply to socket]
H --> I[Client receives response]
The parsed command is then dispatched on the single main thread against the in-memory dataset; a successful write is appended to the AOF buffer and the replication backlog before the reply is encoded and written back to the client's socket.
After parsing, a command is ultimately executed against the dataset by...
A write command that succeeds may be propagated to...
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